Thermoset resins, including unsaturated polyesters and vinyl esters, are commonly employed in a variety of fabrications, such as casting materials, fiber reinforced materials, and coatings. These resins are typically dissolved in an unsaturated vinyl monomer, like styrene, to facilitate crosslinking (curing) and reduce viscosity. The resin is cured with a peroxide type initiator by means of a free radical co-polymerization mechanism to form a solid article. Accelerators are used to promote the decomposition of peroxides.
WO2008003496 discloses a resin composition comprising an unsaturated polyester resin or vinyl ester resin, a manganese compound and a thiol-containing compound and a peroxide compound having formula ROOH, in which R is hydrogen or an optionally substituted alkyl group.
WO2008003495 discloses an unsaturated polyester resin composition comprising an unsaturated polyester resin, a manganese compound, a 1,3-dioxo compound and a base; the resin composition being curable with a peroxide.